The present invention relates generally to manufacturing, and more specifically to microelectronics manufacturing.
The fabrication of microelectronic devices such as semiconductor elements and LCD panels often involves various and repetitive processes. For example, an LCD panel is typically manufactured by submitting an LCD glass substrate to several processes including, but not limited to, a cleaning process for removing particles, a coating process for applying RGB resist and a developing process. Typically, each process is performed using equipment specific to a respective process.
A robot and the like are often configured to transport cassettes containing LCD glass substrates, as well as other semiconductor elements such as wafers, to and from the processing equipment. A robot is generally used when there are a series of programmed processes that need to be performed in a short period of time, typically without intervention. However in the event intervention is required, a robot may not be appropriate. For example, a robot is typically not used when randomly selected samples are conveyed to test equipment between the various processes for such purposes as determining whether the various equipment is functioning normally, or checking the quality of the LCD glass substrates. When unexpected errors occur in the process equipment, programmed process steps are typically unable to be successively performed. The occurrence of process equipment errors typically renders the use of robots inappropriate.
In cases where the use of a robot is inappropriate, cassettes are often conveyed by an operator via a Manual Guide Vehicle (MGV). Because cassettes containing samples often weigh between 50-60 kg, MGVs are advantageous for carrying these heavy cassettes.
A conventional MGV is shown in FIGS. 1 and 2 and is used for transporting LCD glass cassettes. In the illustrated embodiment, the MGV includes a body 17, having a generally hexagonal shape. A load frame 2, having a hexagonal shape, is positioned on top of the body 17. The height of the load frame 2 is less than the height of the body 17. The load frame 2 has a recessed part 29 on the top thereof. The recessed part 29 has an area that is larger than the area of the bottom of an LCD glass cassette 1. The recessed part 29 has a predetermined depth configured to receive a cassette 1. Formed in the center of the recessed part 29, is an aperture 30, which extends through the load frame 2 and forms an aperture 30a on the top of the body 17.
A bar 9 extends through both apertures 30 and 30a. The bar 9 has generally the same diameter as the aperture 30, and is configured to vertically reciprocate therein. The length of the bar 9 is approximately equal to the distance between the recessed part 29 and the bottom portion of the body 17, as illustrated in FIGS. 1 and 2.
The upper end of the bar 9, which extends through aperture 30a in the body 17 is connected to a support 3 and supports the LCD cassette 1, as illustrated. The lower end of the bar 9 is in contact with the bottom portion of the body 17, as illustrated. Only a portion of the bar 9 is supported within the apertures 30 and 30a, as illustrated. Accordingly, a guide 11 is installed at a predetermined location in the body 17, as illustrated. A guide aperture 12 is formed in the guide 11 for guiding the reciprocating movement of the bar 9 inserted therethrough. The guide aperture 12 has generally the same diameter as the bar 9.
The lower part of the bar 9 includes a rack 8 containing teeth on a face thereof. The teeth of the rack 8 are configured to mesh with a pinion gear 7, which is connected to a shaft extending from an electric motor 5. Rotation of the pinion gear 7 via the electric motor 5 causes the bar 9 to vertically reciprocate. The pinion gear 7 includes a lock/unlock member (not shown) for suspending the movement of the bar 9 when the bar 9 is located at a predetermined position.
Still referring to FIGS. 1 and 2, the body 17 further includes a rechargeable battery 13 which is electrically connected to the input terminal of the electric motor 5 and to a charger 15 for charging the rechargeable battery 13 on demand.
The charger 15 is supplied with voltage from an external power supply through an electrical wire. One end of the wire is connected to the charger 15 and the other end is attached to a connector(not shown), which is inserted into an outlet of the external power supply. The charger 15 generally provides Direct Current (DC) output power to the electric motor 5.
Typically, a control knob or a control panel 21 is installed on a handle 19 mounted on the body 17, as illustrated. The power supplied to the motor 5 is adjusted by operating the control knob 21. By adjusting the control knob 21 the motor 5 is selectively rotated in a positive/negative direction to thereby control reciprocation of the bar 9.
Operation of a conventional MGV for transporting cassettes with LCD glasses will now be described. First, an operator operates the control knob 21 to unload LCD glass cassettes 1 from the MGV and load them into processing equipment for performing a respective process. Operation of the control knob 21 causes direct current electrical power to be output from the battery 13, which has been charged by the charger 15 in advance, and supplied to the motor 5.
When the motor 5 is supplied with electrical power, the motor 5 begins rotating in a predetermined direction together with the shaft connected thereto. The pinion gear 7 connected to the shaft rotates in the same direction as the shaft. The rotating motion of the pinion gear 7 is transmitted to the rack 8 at the lower portion of the bar 9. The rack 8 translates the rotating motion of the pinion gear 7 into vertical reciprocating motion of the bar 9.
The rack 8 continuously moves upwardly while the motor 5 is supplied with electrical power. When an LCD cassette 1 reaches a predetermined vertical position, the operator operates the control knob 21 to cause the motor 5 to stop rotating, thereby suspending the upward movement of the LCD cassette 1 via the bar 9. The movement of the bar 9 is suspended via a ratchet which engages with the teeth of the pinion gear 7 to prevent the pinion gear 7 from further movement. The bar 9 then stops its upward movement and is not allowed to reverse its upward direction. When the LCD cassette 1 is at a predetermined height, it is either unloaded from the MGV to the processing equipment or loaded from the processing equipment to the MGV.
Referring to FIG. 3, another embodiment of a conventional MGV is illustrated. The illustrated MGV includes a charger 65 and a rechargeable battery 60 therein. The illustrated MGV includes a first motor 50 connected with vertical screws 40, rather than a rack and pinion, to move the support 70. A recessed portion 75 is formed in the support 70. In the recessed portion is installed a second motor(not shown), which is operably engaged with horizontal screws 77 for horizontally moving an LCD cassette 80. The second motor is electrically connected with the battery 60.
Conventional MGVs, such as those described above with reference to FIGS. 1, 2 and 3 may have several disadvantages. One problem is the increased weight associated therewith. Because the MGVs have a heavy rechargeable battery as well as a charger for charging the battery therein, an operator can find the MGV to be somewhat difficult to pull or push. Another disadvantage is that the rechargeable battery often requires much time to be recharged. Another disadvantage is that an operator is often required to check the charging state of the battery in order to ensure proper operation. Typically, the battery cannot output enough power to move the support vertically if not properly charged. Hence, a smooth process may not result. Still another problem with conventional MGVs is that rechargeable batteries and chargers included therein, typically increase the cost of MGVs.
It is therefore an object of the present invention to provide an MGV which can be of lighter weight than conventional MGVs and, thereby, is easier for an operator to pull and/or push.
It is another object of the present invention to eliminate the need for a rechargeable battery as a power supply.
To achieve the above and other objects of the invention, an MGV according to the present invention includes transporting means for transporting cassettes with samples to and from processing equipments, driving means for driving the transporting means, and power supplying means for supplying electrical power to the driving means. The power supplying means may include a power supplying device, installed on external equipment, for supplying an MGV with electrical power, and a power receiving device, installed in the MGV for receiving electrical power from the external equipment. The power supplying means may further include a first guide unit, installed on an MGV for guiding the power receiving device, and a second guide unit for limiting movement of the first guide unit.
An MGV configured according to the present invention is capable of receiving power for driving a cassette transporting device from external processing equipment instead of utilizing a rechargeable battery and charger system which are typically utilized in MGVs. A power receiving device having a connector portion is installed on the MGV, and a connector portion of a power supplying device is installed on the external processing equipment. The power receiving device includes a connector portion and guide pins. The connector portion includes pins configured to be inserted into the power supplying device in the external processing equipment.
An operator moves an MGV configured according to the present invention such that the power receiving device is aligned with the power supplying device in the processing equipment. Utilizing a foot lever, the operator engages the power receiving device with the power supplying device, thereby providing a continuous supply of electric power from the external processing equipment to the MGV. Operations for supplying power to an MGV for transporting cassettes to and from processing equipment, according to the present invention, therefore, include adjusting the power receiving device of an MGV to the power supplying device of external processing equipment, inserting a power receiving device into a power supplying device, and driving the driving means using power supplied therefrom.
An MGV configured according to the present invention is advantageous because it does not require a battery or a recharger. Accordingly, such an MGV is lighter in weight than MGVs with battery/recharger combinations. The lighter weight makes it easier for an operator to manipulate the MGV during microelectronic manufacturing operations. Furthermore, the MGV does not require time for charging of a battery.